Solr-based suggestion / autocomplete

[kshepherd]

Adds Solr-based suggestion to dynamic onebox vocabulary lookups.

See DSpace/DSpace#10855 for more notes

UI
In the dynamic-onebox Angular component which traditionally handles vocabulary / authority display like tree lookup or autocomplete, if the vocabulary type is "suggest", it will use a different search method and display template for the suggest terms. If not, the current behaviour is used (lookup / suggest from XML / etc)

Like the backend, the actual suggest term JSON is not fully modelled in Angular, it is just treated as JSON. This is done to keep things light (they are not proper DSpace addressable objects or anything, not used anywhere but as input providers) and due to the structure of the JSON where terms are used as key names, etc.

[github-actions]

Hi @kshepherd,
Conflicts have been detected against the base branch.
Please resolve these conflicts as soon as you can. Thanks!

[strawburster]

I'm trying to limit the number of new properties on the onebox component, which is already quite a monstrous little thing. I combined the suggestion api and the vocabulary service into a single observable, and I want to combine the suggestrt/suggestrte templates with the existing rt and rte templates. Other than that, this is working as expected. I may adjust the spinner stylistically.

[strawburster]

This is working the way I want it to. I made large changes to the onebox component, and I plan on adding more tests for it, as well as tests for the new search service method for getting suggestions. The existing tests should all pass (famous last words)